You're using an external library — GtkExtra — and that library still references widgets like GtkCTree which have been long since deprecated in GTK+ 2, and removed from GTK+ 3 (GtkCTree and GtkCList are GTK+ 1.2 widgets which were deprecated when GtkTreeView was added in GTK+ 2.0, 17 years ago). It seems you have a widget that uses the GtkDirTree widget from GtkExtra; that widget inherits from GtkCTree.

You will need to rewrite the widget — either using GtkListBox or GtkTreeView.